Evaporator



July 25, 1933. HBAER wmoso EVAPORATOR Filed June 4, 1932 Patented July 25, 1933 UNITED STATES PATENT OFFICE ALVIN H. BAER, or WAYNESBORO, rE NsYLvANrA, AssIeNon rornIoK ooMrANY,

or wAYNEsBoRo, PENNSYLVANIA, A CORPORATION or PENNSYLVANIA.

EVAPORATOB Application filed fl'une 4, 1932. Serial No. 615,415.

A further objectis to provide an evapora-V 5 toizrequiring small head room for its instal-" lation.

Further objects and advantages will become apparent as the description proceeds.

Referring: to the accompanying drawing,

1 which is made a part hereof and on which similar reference characters indicate similar parts, r I V v F'gure 1 is an end view of the evaporator as it would gapp'ear wheninstalled near the 1 topv of a-refrigeratingcar, I

Figure 2,. a side elevation of the evaporator lligureii, a plan v'iewof the same, a'nd Figure 4, a view similar to Figure -1 of a slightlymodifiedform of the evaporator.

In the drawing numeral 10 indicates the ceiling of a refrigerator car in'which the evaporator may be installed. The evapora-' tor. itself consists of upper and lower head'- ers -11 and 12, connected by bowed riser tubes- 13 and .14. In the form shown in Fig ures 1 to 3, there are two sets of these tubes, the tubes of one set being considerably longer than those of the other set. The

headers 11 and 12 are placedrelatively close together and the'bowed tubes extend laterally so as to providea relatively long channel throughm which the refrigerant passes from the lower to theupper header. The

upper header is larger than the lower since the refrigerant will be sucked from this header, the reduced pressuretendmg to aid in the evaporation of the refrigerant.

Short bent tubes,19 are connectedto the 40 ends of the headers ator near the bottoms of the headers and provide for return to the lower headerof the liquid entrained with the gas and brought into the upper header. These tubes are preferably covered with some heat insulating material 21.

In operation the refrigerant will absorb heat and evaporateto a. gas; the gas, will flow upwards through theliquid from the point where it forms, which may be at any point on the exposed surface of the bent tubes, as well as the headers. As gas is drawn awayfrom' the top header by the suction of the refrigerating machine or compressor, a slightv reduction in pressure.- is created there, and the small bubbles or quantitiesvof gas formedthroughout the bent' tubes will flow upwards partly because of this fact and partly because of the reason of difference in their weight in respect to a the weight of the liquid; just as air bubbles will rise to the top surface of a pail of water.

This will not, however,'serve to create a self circulating system entirely, because the gas bubbles will join each other as they movealong, form larger quantities and tend to push some of the liquid ahead of them, through the bent tubes. Now if there is provided a suitable return passage for theliquid that is lifted towards the upper heador where it will not be disturbed or retarded by the tendency of gas flowing upwards, the excess liquid pushed into the upper header will flow back to the lower header, just as water circulates in water tube boiler with drums above and below, to generate steam.

The tubes at one or both ends of the headers, connect the lower point of the upper header with a lower point on the end of the lower header. When the evaporator is charged with liquid it will be'filled up to the lower level of the upper header, and perhaps a small quantity in the lower side of that header. Liquid pushed upwards will flow back to the lower header at the end. Because of the exposed surface of the lower header also, absorbing heat and creating gas,

' interfere to some extent with the free down:

ward circulation of the liquid.

There is an advantage in a refrigerating 1 0 0 plant for vehicles in having the cooling unit or evaporator located along the ceiling of the refrigerated space as it insures uniform cooling-of the space, A special advantage is secured in that this form of evaporator may be installed where there is a very small head room. iHeretofore such flooded type of evaporators have been 'narrowand high. My evaporator. occupies very small head room and bymaking the width much greater than the over-all height, ample provision is had for heat transfer between the evaporator and the surrounding media while the evaporator unit may beinstalled in arela tively small space. p

In theform of evaporator shown in Figure. 4 there are provided upper and lower the header.

headers 15 and 16, the upper header being considerably larger than thelower header. Bowed tubes 17 connect the headers, these tubes beingbent as shown at 18 and enter ing the lower header in the topportion of The bentportions'of the headers "provide a' somewhat more steeply inclinedpassage from the lower headeras the refrigerant leaves the header. Short insulated tubes 20 connect the ends of the lower with the ends of the upper header to provide for a return to the lower header of any.

liquid-refrigerant carried over by the entraining gas. In this form of evaporator only one set or tubes is provided at each side of the headers instead of the twosets as shownin Figure 1. This form of evaporator is somewhat cheaper than the form shown in Figure 1. f I11 both cases, however,

the headers are placed close together and the bowed tubes which constituterisers extend relatively wide distances laterally to provide long heat transfer channels for cooling the media surrounding the evaporator. It will be obvious to those skilled in the art that various changes may be madein my device'without departing from the spirit of the invention and therefore, I do not limit myself to what is shown in the drawing and described in the specification, but only as indicated by the appended claims. 1

Having thus fully described my said invention, what I claim as new and desirejto secure by Letters Patent,- is:

1. An evaporatorfor a refrigeratingunit the lower with the ends of the upper headers, and a, second series of shorter bowed tubes connecting the lower and the upper headers and ositioned withinthe space defined by the Erst series ofbowed tubes, substantially as set forth r 3. An evaporator comprising an upper and a lower header lying adjacent each other, a plurality of laterally extending bowed tubes connecting said headers, and a pair of shortinsulated tubesc'onnecting the 1 ends of saidheaders, said short tubes being attached near the bottoms of said headers and prviding conduits for returning liquid refrigerant from the'upper to the lower header, substantiallyas' set forth.

4. An evaporator comprising an upper and alower header, positioned approx inately against each other, a plurality of relatively long laterally extending bowed tubes connecting said headers, and a pair ofrelatively short insulated tubes connectingthe ends of said headers, said short tubes being attached near the bottoms of said'headers and providin conduits for returning liquid header, substantially as setforth -5. An evaporator comprising an upper refrigerant from the upper to the lower and a lower header, "a pluralitysof bowed tubes connecting said headers; said tubes being connected to saidheaders in the upper half of the headers, and a pair of liquid refrigerant return tubesconnecting said headers, said tubes being connected to the headers in the lowerv half of the headers,

substantially as set forth, V

6. An evaporator comprising. an upper and a lower header, a pluralityofbowed tubes connecting said headers, said tubes being connected to said headers in the upper half of the headers, and a pair of liquid refrigerant return tubes connecting said headers, said tubes being connected to the headers in the lower half of the headers,

said last-named tubes being covered with a heat insulating media, substantially as set forth. 1

7 An exaporatorv comprising an" upper and alower header, laterally bent riser tubes connecting said headers, and insulated tubes connecting the ends of the upper with the ends of the lower header for returning liquid refrigerant from the upper to the lower header, substantially as set forth.

- 8. An evaporator comprising an upper and a lower header, laterally extending bent riser tubes connecting said headers, and short insulated tubes connecting the ends of the upper with the endsof the lower header for returning liquid refrigerant from the upper I to the lower header, said riser tubes being relatively long to provide a gradualupwardly inclined channel for evaporating refrigerant and said return tubes being relatively short to providequick return of the refrigerant Without evaporation therein, substantially as set forth.

9. An evaporator comprising an upper and a lower header, laterally extending bent riser tubes connecting said headers, and insulated tubes connecting the ends of the upper with the ends of the lower header for returning liquid refrigerant from the upper to the lower header, said riser tubes being relatively long to provide a long upwardly inclined channel for evaporating refrigerant and said return tubes being relatively short to provide quick return of refrigerant without evaporation therein, said riser tubes being connected in the upper half of the headers and said short return tubes being connected in the lower half of the headers and adjacent the ends thereof, substantially as set forth. I

10. An evaporator adapted for use in a chamber having low head room comprising upper and lower headers positioned relative- 1y close together, a plurality of groups of bowed tubes connecting the said headers, a second groupbowed tubes shorter in length than the first named tubes and confined in the space defined by the first group of tubes,

both of said groups of tubes extending laterally to a distance substantiallygreater than the vertical distance between the headers,

headers positioned relatively close together,

a plurality of bowed tubes connectingsaid headers and extending in both directions laterally from the headers to a distance considerably greater than the distance between the headers toprovide a relatively long channel for passage of the refrigerant from the lower to the upper header, substantially as set forth.

A. H. BAER. 

